I've never played WoW personally but it's possible we can snag different races/classes/missions and mix and match from various fandoms for inspiration. I would say any mission/quest could require different types of players. As you mentioned, healers/clerics/medics/etc are pretty useful. I could see some missions/quests requiring them while others wouldn't allow them, maybe for added challenge. In regards to how I see my role, I'm happy to play a healer type or someone who does a bit of both close combat and spells. 

I think having the two players be friends, trade items and look out for one another since they began would also work out and make sense. It would give them a good relationship without us having to struggle to deal with introductions and getting to know each character.

I can work on my CS, were you thinking of using pictures for appearances? If so, real life or anime? If not, just tell me. I'd rather us be on the same page in terms of cohesiveness.